1. Field of the Invention
The invention relates to techniques for simulating the launching of projectiles and for determining the direction of launch.
More particularly, the invention relates to new and improved techniques of simulating the aimed firing of guns, the aimed propulsion of balls by cues or clubs, and the like.
2. Description of the Prior Art
There are many occasions when it is desirable to simulate the aimed launching of projectiles.
For example, it is often desirable to engage in rifle or pistol target practice in close quarters, where the use of real weapons with live ammunition is too noisy, or too dangerous. Also, real weapons and ammunition are costly, and their use normally requires official permission which may be difficult, if not impossible to obtain.
Therefore, a harmless, inexpensive gunfire simulation technique useable for target practice would be highly desirable.
Another example involves toy guns, with which live ammunition can obviously not be used. It is believed that a substantial demand exists for toys which permit simulation of gunfire that is realistic in terms of aiming accuracy and indication of hits and misses.
Attempts have previously been made to provide such simulations, using light to simulate the projectiles. To this end a source of a light beam is mounted in a gun-like structure, and turned on in response to pulling of the trigger in order to simulate the firing of a bullet.
A photocell is mounted on a target at the spot of intended impact of the simulated bullet. If the bullet-simulating light beam strikes the photocell, and does so with sufficient intensity, and electronic circuit lights a lamp, or rings a bell, or otherwise provides an indication of a hit. Absence of such indication signals a miss.
The usefulness of such a simulation depends on several factors.
First, the light beam used to simulate the bullet must be intense enough that, even at the considerable distance at which the target with its photocell may be located, that photocell is capable of distinguishing the beam from the ambient illumination to which the photocell is also exposed. This in itself is a very taxing requirement. Since the gun with its light source must be portable, it is normally battery-powered. This severely limits the intensity of the light beam which it can project. That is especially true for toy guns, which must be capable of being handled by children. Powerful batteries would be too heavy, not to mention too expensive for such toy applications.
Another factor which affects the usefulness of simulation by light beam is the requirement that the beam be so well focused that it reaches the distant target with a small and well-defined cross-section. This is important for two reasons. A broad beam distributes the already inadequate amount of light reaching the target over a large area, and thereby further reduces the fraction of that light which falls on the active area of the target photocell. In addition, if the light beam is spread over an area of the target substantially greater than the active photocell area, then the photocell is no longer able to distinguish between the case when the simulated gun is aimed directly at it, and the case when the gun is aimed incorrectly, but light still reaches the photocell because of the large cross-section of the beam. The photocell then causes a hit to be registered in either case, and this greatly diminishes the effectiveness of the simulation.
This factor creates a particularly difficult problem in attempting to achieve simulation by light beam. The reason is that the optics needed to keep a light beam from diverging too far over normal gun-to-target distances are prohibitively complex and costly for most situations.
Still other, more subtle shortcomings of attempts to use light beams for simulating aimed projectile launching will be pointed out later, in discussing the various aspects of the present invention.